The present invention relates generally to the field of three-dimensional stacked integrated circuits, and more particularly to the field of a power management of a three-dimensional stacked DRAM memory device.
Three-dimensional stacked integrated circuits (3D stacked ICs) comprise two or more IC dies, stacked one on top of the other. Interconnections may be provided by wire-bonding, through-silicon vias (TSVs), and/or interposers. 3D stacked ICs provide higher circuit density, for a given footprint at the next level of assembly (for example a circuit card onto which the 3D stacked IC is mounted).
In high bandwidth data communication, a differential interface minimizes electromagnetic interference. A differential memory interface (DMI) is used to pass data into and out of a memory module with high bandwidth. Information is encoded on an original signal. The original signal is inverted to produce a complementary signal. The original signal is transmitted through one conductor while the complementary signal is transmitted, substantially in phase with the original, though inverted, through another conductor. Both conductors are positioned and routed in close proximity to each other such that external electromagnetic interference (noise) picked up in transmission tends to affect both signals equally (in magnitude and polarity), but has little to no effect on the differential (the difference) between the original signal and the complementary signal. The receiver detects the differential between the original signal and the complement. The amplitude of the differential is substantially double the amplitude of the original signal, thereby doubling the signal to noise ratio. This technique effectively doubles the noise immunity and recovers the transmitted information.